function ifTest(){
    if(!null){
        console.log("null is zero");
    }
    if(!undefined){
        console.log("undefined is zero");
    }
    console.log(parseInt('17', 2))
    console.log(parseInt('7', 2))
    console.log(parseInt('9', 2))
    console.log(isNaN(['123'])) // false
    console.log(isNaN(['xyz'])) // true
}
function cls(){
	var age=0;
	function getAge(){return age;}
	function setAge(a){age=a;}
	return {
        get: getAge,
        set: setAge
	}
}
var t=cls();
    t.set(42);
var t1=cls();
	console.log(t1.get());